Buggy code:
public boolean isVersioned ( ) { } public boolean isVisible ( ) { } public final boolean isVisibleInHierarchy ( ) { } public final void modelChanged ( ) { } public final void modelChanging ( ) { } public final Page newPage ( final Class c ) { } public final Page newPage ( final Class c , final PageParameters parameters ) { } public final void redirectToInterceptPage ( final Page page ) { } public final void remove ( ) { } public final void render ( ) { } public final void render ( final MarkupStream markupStream ) { } public final void renderComponent ( final MarkupStream markupStream ) { } public void renderHead ( final HtmlHeaderContainer container ) { } public final void rendered ( ) { } public final boolean sameRootModel ( final Component component ) { } public final boolean sameRootModel ( final IModel model ) { } public final Component setEnabled ( final boolean enabled ) { } public final Component setEscapeModelStrings ( final boolean escapeMarkup ) { } public final void setMetaData ( final MetaDataKey key , final Serializable object ) { } public Component setModel ( final IModel model ) { } public final Component setModelObject ( final Object object ) { } public final Component setOutputMarkupId ( final boolean output ) { } public final void setRedirect ( final boolean redirect ) { } public final Component setRenderBodyOnly ( final boolean renderTag ) { } public final void setResponsePage ( final Class cls ) { } public final void setResponsePage ( final Class cls , PageParameters parameters ) { } public final void setResponsePage ( final Page page ) { } public Component setVersioned ( boolean versioned ) { } public final Component setVisible ( final boolean visible ) { } public String toString ( ) { } public String toString ( final boolean detailed ) { } public final String urlFor ( final RequestListenerInterface listener ) { } public final String urlFor ( final IRequestTarget requestTarget ) { } public final String urlFor ( final ResourceReference resourceReference ) { } public final String urlFor ( final PageMap pageMap , final Class pageClass , final PageParameters parameters ) { } public final String urlFor ( final Class pageClass , final PageParameters parameters ) { } public final void warn ( final String message ) { } protected final void addStateChange ( final Change change ) { } protected final void checkComponentTag ( final ComponentTag tag , final String name ) { } protected final void checkComponentTagAttribute ( final ComponentTag tag , final String key , final String value ) { } protected void detachModel ( ) { } protected final String exceptionMessage ( final String message ) { } protected MarkupStream findMarkupStream ( ) { } protected final Page findPage ( ) { } protected final List getBehaviors ( Class type ) { } protected final boolean getFlag ( final short flag ) { } protected IModelComparator getModelComparator ( ) { } protected IModel initModel ( ) { } protected void internalBeginRequest ( ) { } protected void internalEndRequest ( ) { } protected void internalOnBeginRequest ( ) { } protected void internalOnEndRequest ( ) { } protected void internalOnModelChanged ( ) { } protected boolean isBehaviorAccepted ( final IBehavior behavior ) { } protected final boolean isIgnoreAttributeModifier ( ) { } protected void onBeginRequest ( ) { } protected void onComponentTag ( final ComponentTag tag ) { } protected void onComponentTagBody ( final MarkupStream markupStream , final ComponentTag openTag ) { } protected void onEndRequest ( ) { } protected void onModelChanged ( ) { } protected void onModelChanging ( ) { } protected final void onRender ( ) { } protected abstract void onRender ( final MarkupStream markupStream ) { } protected final void renderComponentTag ( ComponentTag tag ) { } protected final void replaceComponentTagBody ( final MarkupStream markupStream , final ComponentTag tag , final String body ) { } protected final void setFlag ( final short flag , final boolean set ) { } protected void setMarkupStream ( final MarkupStream markupStream ) { } protected final Component setIgnoreAttributeModifier ( final boolean ignore ) { } protected final Object visitParents ( final Class c , final Component . IVisitor visitor ) { } Component get ( final String path ) { } final boolean isAuto ( ) { } final void renderClosingComponentTag ( final MarkupStream markupStream , final ComponentTag openTag , final boolean renderTagOnly ) { } final void setAuto ( final boolean auto ) { } final void setId ( final String id ) { } final void setParent ( final MarkupContainer parent ) { } final void setRenderAllowed ( boolean renderAllowed ) { } final boolean isRenderAllowed ( ) { } public final boolean isEnableAllowed ( ) { } private final IModel getRootModel ( final IModel model ) { } private final MarkupStream initializeMarkupStream ( ) { MarkupContainer parent = getParent ( ) ; MarkupContainer parentWithAssociatedMarkup = findParentWithAssociatedMarkup ( ) ; MarkupStream markupStream = null ; while ( markupStream == null ) { <START_BUG> markupStream = parentWithAssociatedMarkup . getAssociatedMarkupStream ( ) ; <END_BUG> String componentPath = parent . getPageRelativePath ( ) ; String parentWithAssociatedMarkupPath = parentWithAssociatedMarkup . getPageRelativePath ( ) ; String relativePath = componentPath . substring ( parentWithAssociatedMarkupPath . length ( ) ) ; if ( relativePath . startsWith ( ":" ) ) { relativePath = relativePath . substring ( 1 ) ; } int index = markupStream . findComponentIndex ( relativePath , getId ( ) ) ; if ( index != ( - 1 ) ) { markupStream . setCurrentIndex ( index ) ; } else { markupStream = null ; if ( parentWithAssociatedMarkup instanceof Border ) { parentWithAssociatedMarkup = parentWithAssociatedMarkup . findParentWithAssociatedMarkup ( ) ; } } } if ( markupStream == null ) { throw new WicketRuntimeException ( ( "Unable<seq2seq4repair_space>to<seq2seq4repair_space>determine<seq2seq4repair_space>markup<seq2seq4repair_space>for<seq2seq4repair_space>component:<seq2seq4repair_space>" + ( this . toString ( ) ) ) ) ; } return markupStream ; } }

Fix:
markupStream = parentWithAssociatedMarkup . getAssociatedMarkupStream ( true ) ;